Session J03: CMP + Materials 6: Nanostructures

Controlling light with metallic nanostructures

The control and manipulation of light is a long-standing scientific ambition with profound implications for the development of technology. One of the most promising routes to achieve this goal involves the use of nanostructures with dimensions comparable to the wavelength of light. Metallic systems are especially interesting due to their ability to support collective oscillations of the conduction electrons, commonly known as surface plasmons. These excitations couple strongly with light, generating very large near-fields, and therefore can be used to manipulate light below the diffraction limit. In this talk, we will review the fundamental concepts of plasmonics and discuss some interesting applications of plasmonic systems for the optical detection of molecules. 

Characterization of Platinum Nanoparticles Utilized in Photocatalytic Hydrogen Synthesis

As energy needs grow ever greater in today's world, many scientists are investigating possible replacements for fossil fuels as an energy source. The use of hydrogen (H₂) gas in particular is undergoing a significant amount of research, but a major obstacle in the use of H₂ for green, environmentally-friendly fuel is the energetic and chemical requirement to synthesize the gas.

A possibility in satisfying current and future H₂ production needs is the use of photocatalytic reactions, where a light-absorbing substance acts as a catalyst in shuttling electrons from a donor to protons that are reduced into H₂. Previous research conducted at BYU found such a system where platinum nanoparticles bound to ferritin catalyzed the photoreaction of methyl viologen to reduce protons in an organic acid, which offered a one hundred-fold increase in H₂ production efficiency over photocatalytic reactions catalyzed by bulk platinum.

We are reporting on our efforts to optimize the synthesis of the platinum nanoparticles bound to ferritin that are used in this photocatalytic system and how we characterize these nanoparticles.
  

Modeling of local magnetic ordering in magnetite nanoparticle assemblies

Magnetic nanoparticles (NPs) are a vital part of many applications in biomedicine and other nanotechnologies. There is a growing interest in NP for drug targeting, MRI, and bio-separation. Magnetite NPs stand to be effective in these roles due to the non-toxic nature of magnetite and its ease of manufacture. To be more effectively applied in these applications, a greater understanding of the magnetic behavior of magnetite NPs is needed. This research seeks to discover the local magnetic ordering of ensembles of magnetite NPs occurring at various stages of the magnetization process. To complete this study, we use coherent x-ray magnetic scattering, which provides a unique fingerprint of the magnetic order in the material. I will present modeling results using a one-dimensional model of NP chains with a mix of ferro and antiferromagnetic ordering.